Surveying is used for identifying subterranean elements, such as hydrocarbon reservoirs, freshwater aquifers, gas injection reservoirs, and so forth. Surveying can include seismic surveying or electromagnetic (EM) surveying. In seismic surveying, seismic sources are placed in various locations above an earth surface or sea floor, with the seismic sources activated to generate seismic waves directed into the subterranean structure.
The seismic waves generated by a seismic source travel into the subterranean structure, with a portion of the seismic waves reflected back to the surface for receipt by seismic receivers (e.g., geophones, hydrophones, etc.). These seismic receivers produce signals that represent detected seismic waves. Signals from seismic receivers are processed to yield information about the content and characteristic of the subterranean structure.
EM surveying involves deployment of one or more EM sources that produce EM waves that are propagated into the subterranean structure. EM signals are affected by elements in the subterranean structure, and the affected EM signals are detected by EM receivers, which are then processed to yield information about the content and characteristic of the subterranean structure.
In addition to survey sources and survey receivers, a survey system can also include concentrator units to enable communication among different components of a survey system. A network interconnecting different elements of the survey system can be implemented completely or partially with fiber optic links. In most cases, the concentrator units can be interconnected by fiber optic links. Conventionally, to awaken (initially power up) components of a survey system, special wakeup commands or messages are sent by a controller to various components in the survey system, including the concentrator units. Each component that is awakened by such special messages has to analyze the content of the messages to determine whether or not the particular component should wake up. However, such conventional techniques for waking up components of a survey system are not very efficient.